Ms. Aydin works in the Windows program all day. The Blazor page from lesson M4.3 sits in the browser, in another window, with a different sign-in and a bookmark she would have to remember. For the transition there is a way that spares her that: the same page inside the Windows program. Microsoft calls this Blazor Hybrid and describes that Razor components then run natively in the Windows process and render into an embedded web view control: not in the browser, and without WebAssembly. For Windows Forms and WPF, Blazor supplies one BlazorWebView control each. Microsoft's documentation says what it is meant for: bringing new user interface into existing desktop programs, which can be reused on the web and with .NET MAUI. That is exactly what we do.

The bridge is a transition, like the protective layer and the switch: it leaves the old program standing as a shell while the pages are already the new ones. When the old program is switched off (lesson M6.5), the bridge is removed, and the pages run on their own in the browser. That is the reason the components sit in a class library and the window knows nothing about them except their name.

What you need

Microsoft's tutorial for Windows Forms lists the steps, and they are short:

Step What
1 The project uses the SDK Microsoft.NET.Sdk.Razor instead of Microsoft.NET.Sdk (first line of the project file)
2 The NuGet package Microsoft.AspNetCore.Components.WebView.WindowsForms
3 _Imports.razor in the root folder with @using Microsoft.AspNetCore.Components.Web
4 A wwwroot folder with index.html: it contains an element <div id="app"> and the script _framework/blazor.webview.js
5 In the window, a BlazorWebView, with HostPage pointing to the file, Services with the services, and RootComponents.Add<T>("#app")
6 The services include AddWindowsFormsBlazorWebView()

The tutorial also names what you should not do: in the designer's toolbox, next to BlazorWebView there is also a plain WebView2; anyone who drags the wrong one has a control without Blazor. We bypass the designer: the Order Book's forms are created in code anyway (lesson M1.2).